This invention relates to a system for the drainage of body cavities, in particular renal cavity systems, and consists of a flexible drainage tube with at least one crooked end, a tubular device, or pusher, designed to push forwardly the drainage tube into the body cavity, a distal end of which is connected in a separable manner with a proximal end of the drainage tube, and a guide wire passing through the drainage tube and the Pusher.
Such systems are known in various forms of construction. Such a drainage tube serves to hold open narrowed, natural or artificial, body channels and to ensure transport of body fluids from one hollow organ to another or, as well, from hollow organs or layers of tissue to outside. The pusher and the guide wire serve to insert the drainage tube into the body channel to be held open.
A particular field of application is the drainage of renal cavity systems. In this context, it is necessary to insert such a drainage tube into a ureter which connects the renal pelvis and urinary bladder. To that end, a drainage tube which is, at least at one end, but preferably at both ends, crooked like a "J" or even rolled like a "pigtail" has proven to be particularly successful. Drainage tubes crooked at both ends are also known under the designation "Double J" or "Pigtail". The guide wire serves in this connection to extend the crooked ends of the drainage tube. Such a system is produced and marketed by the inventor's assignee under the designation "Integral-Uretersplint-Set", see for instance Willy Rusch AG's catalogue from 1986 "Urologie II/6".
The purpose of the crooked ends of the drainage tube is to anchor the drainage tube through its ends in the renal pelvis and in the urinary bladder, respectively, and to prevent thereby the drainage tube from drifting in the ureter. It can be easily seen that introduction of the drainage tube not only requires the axial shifting thereof, but, if necessary, also rotation thereof, in order to bring the crooked ends into the hollow organs in correct positions for faultless fit. In this context, forces required for shifting and rotating the drainage tube are transmitted by the Pusher which, for this purpose, is firmly connected with the drainage tube.
After insertion of the drainage tube, the guide wire and the pusher must be removed. While the guide wire may simply be pulled out of the drainage tube and the tube-like pusher, the connection between the drainage tube and the pusher has to be interrupted. Known systems present a firm connection between a pusher and the drainage tube, which has to be interrupted by means of a special device. Carrying out such an interruption is extremely difficult, since a separating device has to be inserted either through a cystoscope used for insertion of the drainage tube or else directly through the ureter. In another known system, a pusher is wedged mechanically with a drainage tube; however, such a system is also unsatisfactory because the wedge connection may prematurely loosen uncontrollably during insertion of the drainage tube, or become so fixed that a later separation is no longer possible without difficulties.
Therefore, an object of the invention is to connect, within a system described above, a pusher with a drainage tube in such a manner that faultless transmission of forces required for placing of the drainage tube is ensured, while, however, the connection between the drainage tube and the pusher remains easily separable.
The problem is solved, according to the invention, in the following way: Connected ends of drainage tube and the pusher are equipped with complementary parts of a lock which present mutually overlapping sections; the latter have face sections fitted onto each other, being suitable for the transmission of axial traction forces as well as torque, and being held meshed by means of a guide wire passing through, or permeating, them.
With a system according to the invention a perfect, form-fitted interlocking connection between the pusher and the drainage tube is created by means of a lock, the parts of which are locked by the guide wire. This connection provides an unimpeded transmission of all axial forces and torques from the pusher to the drainage tube. The said connection is, however, undone as soon as the guide wire has been pulled out, since then the two parts of the lock are no longer held together but tend to separate by themselves because the end of the drainage tube connected with the end of the pusher, which so far had been extended by the guide wire, now moves to return its crooked position and thereby separates from the end of the pusher. Therefore, it is advantageous if the faces ensuring the power transmission are arranged on an outer face of the crooked end of the drainage tube.
In a preferred embodiment of the invention, each part of the lock presents at a spaced distance from its end a transverse slot and a section delimiting, or defining, the transverse slot has on its periphery a flattening parallel to a base of the slot. In this system, each part receives in its transverse slot the section of the other part delimitating the transverse slot, and the section delimiting the transverse slot of one part is fitted with its flattening onto the base of the slot of the other part, respectively. The sections meshing with the transverse slots of the other parts, their faces being laid at right angles to an axis of the drainage tube and the pusher, ensure a faultless transmission of axial traction forces, whereas a form-closed interlocking fit between the parallel flattenings of the sections delimiting the transverse slot and the, respectively, adjacent slot base also guarantee a faultless transmission of torques. In this respect, it is particularly advantageous for holding the parts of the lock perfectly together, if the transverse slot intersects with the bore of the part, since in that case the section delimiting the transverse slot also presents a closed bore through which that section is perfectly centered with the guide wire.
The parts of the lock may be formed by certain parts which are fitted into the drainage tube and/or the pusher, but they may also be formed directly as part of the drainage tube and/or the pusher. If fitted parts are used, they may consist of any sufficiently firm, medically safe material, preferably of metal or plastic.
In a further embodiment of the invention, the lock is supported by a sleeve.
This has the advantage that a drainage tube connected with a pusher can be threaded coaxially on an already set spiral mandrel. For that purpose, a tip of the drainage tube features a perforation through which the drainage tube can be threaded onto the spiral mandrel. As soon as the spiral mandrel has pierced bore openings of the lock, the sleeve can be removed. The lock is held together in a centered manner by the spiral mandrel.
In still another embodiment of the invention, a sleeve can be snapped open in two halves.
This has the advantage that complementary parts of the lock can be firmly pressed together and that the sleeve has an axially immovable fit at the end of the pusher and the drainage tube. As soon as the spiral mandrel holds together the parts of the lock, the sleeve may be taken off the ends of the drainage tube and the pusher simply by snapping open the halves of the sleeve.
After termination of the described drainage, the drainage tube has to be removed again from the body cavities. This removal is obtained through known methods, in particular through an endoscopical intervention. If the drainage tube is to remain only for a short time, it has proven successful to fix thin threads to the drainage tube which hang out of the body channel, for instance the ureter, so that removal of the drainage tube may be obtained by pulling ends of the thread. In a system according to the invention, it is possible to attach at least one thread to the lock part of the drainage tube which is so long that, the drainage tube being in place, it protrudes from the body cavity and thereby allows the drainage tube to be pulled out.
In the following, the invention is described and explained in more detail by means of embodiments of the invention as presented in the drawings. The characteristics as they appear from the description and the drawings can be applied individually or in any combination in other embodiments of the invention.